Vegetable glue or adhesive.



TINTTED snares Parana canton.

RAYMOND WELCH 'I'UN N ELL, 0]? PHILADELPHIA, PENNSYLVANIA.

VEGETABLE GLUE 0R ADHESIVE.

No Drawing.

from starch which has been modified or hydrolyzed by the action of acids or alkalis on the aqueous solution. The resultant product is a degenerated starch glue with increased adhesiveness.

' The object of myinvention, however, is to increase the binding power of previously known starch glues, making the same more waterproof, and enhancing the appearance.

In preparing glue it has been the custom to treat a mixture of starch and water with a certain percentage of caustic alkali-in order to make a viscid, adhesive paste; but the alkali affects the starch and forms substances such as lactic or mucic acids, or compounds of similar nature, which become apparent when the paste is heated by the re-- sulting brown color of the paste. The formation of such compounds in the paste seems to decrease the strength of the same.

Since vegetable glue acts more like a cement than a true adhesive, it is desirable to make the paste more waterproof. This I obtain by forming in the body of the dried paste some insoluble compounds. To this end, I add a small percentage of a salt to the solution of the starch mixed with the caustic alkali, which will give a hydroxid of the metal or metals forming the salts. The bydroxid formed reacts with the acid, or acids, that is generated by the action of the caustic alkali on the starch and probably forms a salt which renders the starch insoluble.

The salts I prefer to use are those giving" white oxids, so that when the paste is dried and if oxids of those salts are formed they increase the whiteness of the paste and therefore, enhance its appearance. Furthermore, the salts used are of a character that would produce slimy or gelatinous hydroxids, which would tend to increase the ad- Specification of Letters Patent.

Patented May 14, 1918.

Application filed November 9, 1917. Serial No. 201,118.

hesiveness and body of the paste, in addition increasing its waterproof quality. As an example of such salts, I may cite chlorid of zinc.

In preparin the adhesive I may make use of the old wel known methods of treating one of the many forms of starch from its various sources, such as tapioca, sago, potatoes, or from other sources, in order to hy-- drolyze or convert such starch to the point of producin a density flow or viscosity of the degree esired. In such cases I follow former well known methods in grinding, mixing or agitating the selected starch with enough water to produce a paste of the proper consistency. The percentage of water to starch varies with the source and characteristics of the latter.

When the paste solution has been brought to its proper consistency, I add to the same,

as in previous well lmown cases, the necessary percentage of caustic soda or other alkali to digest the starch or hydrolyze it. Thus far I claim no novelty. To the resulting solution I then add from 5% to 50% of a chlorid of zinc, as compared to the weight of the caustic soda used. The quantity of the salt added depends 'on the desired viscosity of the resulting product, if the same is to be used at once. If it is to be marketed,

it is preferably dried. The paste can then be formed by adding a quantity of water to obtain the desired -viscosity of paste.

The zinc chlorid added to the hydrolyzed starch forms, probably, a zinc lactate, or a zinc salt of a similar organic acid. formed by the reaction of the starch solution with the caustic soda. The zinc lactate, being sparingly soluble, precipitates and is dif-' fused in the body of the starch. The drying of the starch compound will not alter the zinc lactate, and if it does alter it it will be transformed into a zinc oxid. which is sparingly soluble, thereby not afiecting the adhesive when the same is mixed with water to use as a cement.

From the above it will be seen that in my method of subsequent treatment of starch solution salts are introduced which will produce an insoluble salt of an organic acid, which organic acid is produced by the reac tion of the salt solution with the starch. It is probable that the acids used are of complex nature and, therefore, it would be im- Q I a, ch se a possible to state the exact compositicnor l claim: the exact group to which those acids belong; 1. An adhesive formed of hydrolyzed 20 but at all events, the ultimate fact is that starch and a zinc chlcrid.

they do produce insoluble compounds-which 2. An adhesive formed of hydrolyzed are White and which when heated to a comstarch, a zinc chlorid and an excess of causparatively high temperature may decomt 1G.- i pose and form oxide which are also s ar- 3. An adhesive formed of a. mixture of 25 ingly' soluble and which are also White. he starch, water, caustic, and zinc chlorid,ther e diiiusion of the salts of the organic acids being an excess of caustic in the mixture. formed by the starch and the added metal 4. The process of making; adhesive from produces insoluble compounds which instarch which consists in mixing starch, wacrease the Waterproof quality of the adheter and caustic to form a v-iscid mass, and 30 sive and also adds to its whiteness, enhancadding a zinc chlorid to said viscid mass.

ing the'appearance of the product; and, as 5. The process of-making adhesive from has been pointed out, the waterproof quality starch compounds, which consists in treatof the compound is not afiected whether the ing the hydrolyzed starch or its derivative same is marketed as a solution or in dry with a Z1110 chlorid. form; EAWAUND WELCH Tmmg 

